Surface-abrading device



. June2, 1925. T 1,540.591

R. 1.. BARKER SURFACE ABRADING DEVICE 7 Filed Jan. 7, 24 I 2 Sheets-Sheet 1 IWZMMZAQ w June zz,

. 1,540591 R. L." BARKER SURFACE ABRADING DEVICE Filed Jany'r 4 2 Sheets-Sheet a ZQBa I-Zer Patented June 2, 1925.

I To all whom it may concern:

UNITED STAT RAYMOND I BARKER, or; CHICAGO, ILLINOIS.

sUnrAcE- BnAnING DEVICE,

"-A ucati n filed January 7, 924. Serial No. 884,697. I

, or sanding devices which are adapted to be moved along the work to be treated, and

more espe'ciallyto that type of abrading. devices which carry individual driving motors- One object of my invention is'the provision of supporting rollers so disposed that the :tend to carry the device along the work-[o liquely to the abrading element whereby a faster'and more perfect cutting mav be effected; I

ongI-its other objects, my invention contemplates improved means for adjusting the depth of the abrading out, for securing the sand-paper or other abrading element to a rotary drum, and for housing the gears between the motorand-the abrading drum.

The accompanying drawings illustratethese and other features of my invention as I prefer to employ. it,

Figure l'being a plan viewof the abrading device; 1 I

Figure 2, a vertical longitudinal section thereof taken along the line 22 of Fig ure 1; I g

Figure 3, a transverse vertical section along the axis of the drum taken on the line 3-3 of Figure 2;

Figure 4, a detail vertical section taken along the line. 44 of Figure 1. showing the electric switch housed by one of the han-- dles; and

Figure 5, a detail section taken on the line 5-5 of Figure 3, showing the means which clamp the sand paper to the drum.

Theabrading device here shown com-- prises in general a rotary sanding drum 10 mounted within a housing 11 and driven by an individual electric motor 12, the housing being pivotally mounted by a rod 13 to a carriage 14 adaptedto be carried along the work by a pair of rollers 15; Because of their pivotal connection, the housing and the carrlageconstitute in efiect a hinged.

. f 11,540,591 ES PATENTVOFFICE,

frame for the drums The periphery of the drum 1 0 is covered by a sheet of sand paper or other ;,abrading element 16 secured by means which will later be described. A shaft 17 extends'throughthe drum 10, and at eachend thereof is providedwith ball bearings 18 and 19 for journalling the drum within the housing- 11.. To one end of the shaft 17" is secured apinion 20 which is driven through a spacing gear 21 by the driving-pinion 22 of the electric motor 12. v

The armature shaft 23 of the motor is similarly journalled by ball bearings 24 and 25 to the housing 11.

From Figure3, it will be seen that the housing is divided by a vertical partition 11 and a horizontal partition 11 into three compartments, one containing the, drum 10, I

the second, the motor 12, and-the third, the gears 20, 21 and '22. By thus enclosing the three above mentioned units in separate compartments, there is no opportunity for oil or grease from the ring compartment to get to the drum a'n hence to "the work, and similarly, dust carried up -by the'clrum cannot find .its way. into the 1 motor com 'part-ment nor into the gearing compartment. The bottom of the drum compartment is, of course, left open allowing the drum to extend downwardly to the work, to be abraded. p

The armature shaft 23 {preferably carlies a fan 26 adapted to draw air through a plurality of suitable holes 27 in the hous} ing for the purpose of cooling the motor, the warm air preferably being discharged through holes in a closure plate 28. Access by may be had to the motor compartment the removal of the closure plate 28. By means of felt washers 29, substantially oiltight seals are made around the bearings 25 and 18, allowing the gear compartment to be filled with lubricating oil. Access may be had to the several gears by removal of the plate 30 which extends acrossoneend of the housing.

The carriage 14: comprises a pair of lateral rails 31 and transversely extending end rails 32, the end rails being oblique to the lateral rails whereby the carriageis given a trapezoidal-contour. The ro1lers'15 are provided with trunnions 33 for journalling them in the lateral rails of the carriage parallel with the end rails 32. As clearly shown in Figure 1, the rollers 15, while Since the rollers 15 tend to carry thedevice along the work in a direction at right angles to their axes, the drum is moved obliquely. to its rotary or driven direction -whereby the surface of the work is given a somewhat diagonal abrasion. One of the advantages of sucha diagonal cutting action is that a large piece of grit on the abradlng element will not tend, to dig a groove along.

the surface ofthe work. A faster cutting action is also made possible because the work canbe cut partly across the grain of the work rather than wholly with the grain.

While I have shown this feature applied only 'to a device having the abrading element wrapped about the surface of the drum, it is obvious that the invention could be applied to those devices wherein the abrading element is in the form of-an endless belt.

' As previously mentioned, the housing 11 is pivotally secured tothe frame 14 b a rod 13'. The pivot rod 13 is supported at its ends in the lateral rails 31 and passes through lugs 34 extending outwardly from adjacent the base of the housing 11 and ad j acent the respective lateral rails of the carriage. 'At the opposite side of the housing, I provide a bridge 35 extending between the lateral rails and parallel with the housing,

the mid portion of the bridge being formed as a boss 36 through which is threaded a vertical adjusting screw 37, the lower end of which screw carries a knurled thumb disc. A knurled lock nut 38 is provided for locking the screw 37' at the'desired height relative to the bridge 35. A 1ug39 extends outwardly from. the adjacent wall of the housing 11, and through a suitable aperture in the lug extends the upper and reduced end 37 of the screw 37. This reduced portion 37 is threaded and provided with a thumb nut 40 for limiting the upward movement of the lug '39. A compression spring 41 is interposed between the lug 39 and the bridge 35 for urging the housing upwardly about its pivoton the rod .13 to lift the drum 1O above'tliebottom of the rollers 15 and out of engagement with the work.

It is to be observed that the pivotal axis of the housing as it swings upon the rod 13 is parallel with the axis of the drumor more accurately, with the line of contact between the periphery of the drunrand the surface of the work. In this way I over come any tendency to form ridges or grooves caused by'one end of the abrading element digging more deeply into the work than the other end.

In using the abrading device, the operator grasps the handles 42 and 43 secured to the front andrear sides of the housing 11 and pushes downwardly upon the handles as he reciprocatesthedevice along the work .to be abraded. Pressure on the handle 43 this shoulder above the bridge 35, and consequently the depth of the cut madeby the abrading drum, may be adjusted by unscrewin the lock nut 38 and turning the screw 3 to the desired height when the screw may again be locked'by the nut 38. As soon as the operator removes thepressure from his hands, the spring 41 will lift the housing suffioiently to carry the drum out of engagement with the work so that no grooves will be formed therein when the machine is not being moved. The heightto which the spring carries the drum may be varied of course by the thumb hut 40 on the upper end of the screw .38.

I prefer that one of the handles 42 or 43 house the switch mechanism which controls the motor 12, so that the operator may be able to start and stop the machine with the greatest convenience. In Figure 4, I have shown the handle 43 hollowed by a suitable bore, within which is inserteda switch me chanism 44 of a well known type wherein the manually engageable lever 45'is adapted to snap a moving contact member 46 into engagement and out of engagement with a stationary contact member 47. f

4 I shall now' describe in detail the means previously referred to for securing the sandpaper 16 or other abrading element to the periphery of the drum 10. The drum is provided with a bore 48 extendinglongi- 't-udinally thereof from end to end and.

spaced a short distance inwardly from the periphery of the drum. IVitl1in the bore 48 isrotatably mounted a pin 49 extending the length of the drum. At a plurality of spaced points the pin 49 is turned down to' form eccentric reduced portions 50 which constitute crank arms. Over each of these crank arms 50 is hooked a J-shaped rod 51, the straight end of which is secured in a wedge strip 52, which clamps the ends of the san paper strip in a slot 53 provided in the periphery of the drum. One end of the pin 49 is slotted as at 49, whereby a screw driver may be used to rotate the rod to swing the eccentric arms 50' outwardly from the -center of the drum and release the [wedge strip'52along the ends of the sand paper strip 16 to be withdrawn and replaced by a newstrip of sand paper. To relock the sand paper upon the periphery of the drum, the

pin 49 again turned to swing the crank arms 50-'-inwardly, pulling the wedge strip 52 into the slot 53 to clamp the ends of the sand paper. .For locking the pin 49 against 'ti0I1 of a carriage, a single abrading drum tapped into the end of the drum for holding awasher 55 which overlaps a portion of the end of the pin 49 to against rotation.

As shown by the dotted lines of Figure l, the slot 53 extends somewhat obliquely along the periphery of the drum 10, so that at all times during the rotation of the drum a portion of the abrading element is in actual contact with the surface of the work. Even though the drum is rotated at high speed,

this biased position of the break in the abrading element tends to eliminate vibration which would otherwise becaused by the periodic impact of the posterior edge of the slot.

, Having thus described the preferred embodiment of my invention, I claim: 1. In a portable sander unit, the combinapivotally supported on said carriage, means for driving said drum, the rotation of said drum tendlng to confine motion of said carriage along a path at right angles to the axis of said drum, and a pair of rollers on said carriage disposed at an angle to said drum for compelling said unit to travel along a divergent path.

2. In a portable sander unit, the combina- 'tion of supporting means, a single power driven sanding element mounted on said supporting means, the motion of said sanding element tending to cause said supporting means to move along a path in a definite angular relation to said sanding element, and

a roller on said supporting means for' 'compelllilng said unit, to travel along a diiferent pat 3. In a portable sander unit, the combination of a carriage, rollers adjacent the front and rear ends thereof, a frame pivotally supported on said carriage, a single abrading drum pivotally supported on said frame, means carried by said unit fordriving said drum, handle means for depressing said frame to bring said single abrading drum into engagement with the work intermediate the ends of said carriage, the rotation of said drum tending to direct motion of said car-J riage along a path at right angles to the axis of said drum,'one of said carriage rollers be".-

"ing disposed obliquely to said drum for compelling said unit to travel along'a path at right angles to said roller.

4. In a portable sander unit the combina tion of a carriage of general trapezoidal form, a roller at the front end of said carriage, a roller at the rear end of said carriage, a frame pivotally supported on said carriage,

a single abrading drum pivotally supported on said frame, with its axis oblique to the axis ,of said rollers, power meanscarried by saidzzunit for 'dllVll'lg said drum, sprlng means normally holding said frame raisedclamp the latter securely vsaid frame, the obliquity of said drum tendwith said drum out of contact with the surface to be abraded, handle means for depressing said drum into contact with the Surface at a point intermediate the ends of ing to direct motion of said carriage along One path and said end rollers compelling motion of said carriage along another path.

'5. A surface abrading device comprising a frame adapted to rest upon and be moved along the surface of the work to be abraded, and a housing adjustably secured thereto, said housing being partitioned into three compartments, the first housing an ,abrading drum, the second, an electric motor for drlving said drum, and the third, gearing between said motorand said drum, whereby oil is prevented from passing from the gearing to said motor or said drum, and dust is prevented from'passing to said gearing or said motor, said first compartment having an opening at the bottom thereof through which a portion of said drum extends.

6. A surface abrading device comprising a carriage adapted to rest upon and be moved along the surface of the work being abraded, a housing pivotally mounted on said carriage, which housing encloses and supports an abrading drum, a motor for driving said drum, .and a power transmitting mechanism between said motor and said drum, said housing being partitioned into three compartments which contain respectively the said motor, drum, and mechanism, and a handleon said housing whereby the operator may move said device along the work and whereby the operator may push said druminto engagement with the work. V

7. In a portable sander unit, the combination of a carriage, rollers at the front and rear ends of said carriage, a housing pivotally supported on said carriage, an abrading drum pivotally supported in the lower portion of said housing with its axis oblique 110 to the axis of said rollers, an electric'motor enclosed in the upper portion of said housing a partition forming a gear comcontact with the work surface, handles projecting from the opposite sides of said housing for rolling said carriage and for depres'singsaid housing, and screw threaded abutment means between said housing and said carriage for limiting the depression of said housing. v

8. In a portablesander unit, the combination of a carriage, rollers at the front and rear ends of said carriage, a housing disposed intermediate said rollers, pivot'lugs projecting from said housing, pivots connecting said lugs to said carriage, an abradthe work at a ing drum pivotally' supported in the lowerportion of said housing, an electric motor pivotal ly supported in'the upper portion of said housing, a partition separating the I drum compartment from the motor com-" drum shaft in said last named compartment, an idler gear-in said compartment connect.- ing said gears, a support carried by said carriage, a lug on said housing, a spring confined between said support and said lug for" normally holding said housin q in raised position, an ad ust able screw threaded abutment means between said support and said lug and a handle for depressing said hous ing, said abrading roller contacting with point intermediate the ends of said carriage.

9. In a portable unit of the class described, the combination of. a carriage having front and rear rollers, a housing pivotally supported on said carriage, a first par-- tition. in said housing forming a drum coin-- partment and a motor compartment, an

.abrading drum in'said drum compartment,

an electric motor in said motorcomparts ment, a second partition in said housing forming a gear compartment separate from said first named compartments, the shaftso'f said motor and of said drum extending through'said second partition into said gear compartment, bearings carried by said second artition forsaid shai gears on each ;of said shaft-s means in said gear compartment operatively connecting said gears, packing means associated with said bearings for excluding the lubricant in said gear compartment from saidmotor and drum.

compartments, and air iinpelling means for circulating air through 'saidmotor compartment. -g p -In witness whereof, I'hereunto subscribe my: name this 31st da of December,-1923.

RA. OND,L.. BARKER. 7 Witness:-

J DAVID DICKINSON. 

